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Brake Lining


stevem75
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I have used both cast iron and steel. No sure what grade of steel I have used but it was a disaster and I would never waste my time again with steel. Despite trying different grades of brake liner material I just could not make it work, On the other hand my experience with cast iron has resulted in brilliant brakes. The front brake on my 199 easily works with just one finger. Newfren liners do not work well with cast iron to be honest in my opinion they seem not to work well with any material!. I use fork lift truck lining material bonded onto original shoes by a company in Yorkshire.(saftek)

 

Cast iron is difficult to obtain in tube form. I buy a slice from a solid bar usually from College Engineering Supplies in Birmingham (UK) who will cut a blank to my exact width. Expensive but it least you can get it. I then drill a series of holes and cut or knock out the middle which goes in the scrap box for possible other jobs. Then onto the lathe. The first cuts are interesting as the jagged surface from the holes gives the tool and lathe a very hard time. It takes me a couple of hours to produce a blank for final machining but my time in the workshop in the evenings is cheep. Domestic oven in the kitchen to heat the hub prior to final assembly. After 30 years of marriage my wife is used to this and also finding cast iron rings in the freezer.

 

Stuart

 

Thats very interesting Stuart. How much would you charge for a service like this, pm me if you like?

 

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Consider stainless steel pipe. 304 or 316 or their L grades.

 

The pipe, about 15mm wider than finished liner is tack welded to a fabricated face plate. The ID and OD are then turned on the lathe, alternating the final cuts between ID and OD to ensure they are concentric. Liner is then cut off face plate but with extra width left on. Hub is then heated, liner chilled and the two pressed together. Spare width is then machined off (can be done with cutting disc in angle grinder)

Stainless steel has a coefficient of thermal expansion closer to aluminium than steel or cast iron.

There is a bit more to the job than I have stated but anyone with the skills to do the job will know how to do what I have not covered.

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I would use the L (low carbon) grade stainless steel. EBC claims a 20% higher friction value when using low carbon Stainless steel.

But how does the friction value of stainless steel compare to normal steel?
Because the main reason of the re-lining, for most of us, is improving brake power.

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I would use the L (low carbon) grade stainless steel. EBC claims a 20% higher friction value when using low carbon Stainless steel.

But how does the friction value of stainless steel compare to normal steel?

Because the main reason of the re-lining, for most of us, is improving brake power.

 

Re lining on a Bultaco is down to the chrome linings failing.

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Thats very interesting Stuart. How much would you charge for a service like this, pm me if you like?

 

Sorry,

 

I work full time and all my spare time is currently being spent on my BSA restoration and the half complete bathroom my wife seems to want finished for some strange reason.

 

Stuart

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Re lining on a Bultaco is down to the chrome linings failing.

 

Could be, but I'm sure many were glad they finally had a reason to replace the lining with something that actually has some friction.

 

I know I was :)

 

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Mmmh I don't know how bad your brakes are. The ones on my bike work astonishing well having still the chrome. I use original brake shoes (over 30 years old NOS) and had them aligned to the drums, which was quite a job. The outcome is what I need.

If you are braking with the wrong area of the brake shoe you can get very little braking power. So I recommend too to look up how well the shoes fit to the drums.

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I think it was Charles Coutard who used to drill the friction area of his Bultaco hubs so they looked a bit like a cheese grater and gave good braking wet or dry.

What pschrauber says in #24 is very relevant. Shoe to drum alignment is vital for good performance. There is a design flaw in pretty well all trials bike drum brakes in that one end of the shoe pivots on a round pin and so cannot slide to find its most effective location on the drum. Car brakes are designed so the shoes slide to align with the drum.

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I had recently my bike at the technical inspection to get it road registered after the rebuild was done. The bikes origin is from Torino Italy so I had to go through a §21 as we call it which means everything was tested. The brakes are capable to lock the wheels and the bike could be stopped on the road in suitable length. I think it depends beside the correct align between drum and shoe also to the right pad material.

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Could be, but I'm sure many were glad they finally had a reason to replace the lining with something that actually has some friction.

 

I know I was :)

 

 

See scraubers answer, strangely the bulto brakes worked ok with chrome and saved weight too.

But the reason for change back then and now is the failing suface, no could be about it.

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"There is a design flaw in pretty well all trials bike drum brakes in that one end of the shoe pivots on a round pin and so cannot slide to find its most effective location on the drum."

Which is why the Fantic 300 and the last drummed braked YZ's worked so much better ...Self centering brake shoes ... And then came the disc's ...:)

Glenn   B)

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